Amelia House, a senior living provider based in Council Bluffs, Iowa, asked the same question and came up with some interesting answers.

Using data from the Census and United Health Group's (UNH) EverCare 100@100 Survey, the firm finds that long life is not all about family tree. While 20% of longevity is tied to genetics, 80% is based on "lifestyle" choices. Among Amelia House's tips for living to 100 and beyond:

Socialize. 80% of Americans over 100 talk to a family member or friend every day.

Eat well. 75% of centenarians eat a daily diet full of nutritionally balanced meals, and another 32% rely on organic food as a mainstay.

Get plenty of sleep. 75% of 100-year-olds get at least eight hours of sleep every night.

Laugh. 72% of 100-year-olds laugh every day - a lot.

Be at peace. 62% of centenarians pray or meditate every day.

Some other traits to consider:

Volunteer. 17% do charity work on a regular basis.

Make like a teenager. 12% of 100-year-olds listen to music on an iPod or similar device. Another 11% watch YouTube, and 8% send text messages to friends and family members.

Amelia House says that centenarians tend to live in close-knit communities, suggesting that older retirees who live on their own are at greater risk of serious health issues. Another big help is living "close to nature," where older retirees can walk, visit with friends and family in a healthy city and engage in light exercise.